The syntheses of a family of highly ordered mesoporous polymers and carbon frameworks from organic−organic assembly of triblock copolymers with soluble, low-molecular-weight phenolic resin precursors (resols) by an evaporation induced self-assembly strategy have been reported in detail. The family members include two-dimensional hexagonal (space group, p6m), three-dimensional bicontinuous (Ia3̄d), body-centered cubic (Im3̄m), and lamellar mesostructures, which are controlled by simply adjusting the ratio of phenol/template or poly(ethylene oxide)/poly(propylene oxide) in the templates. A five-step mechanism from organic−organic assembly has been demonstrated. Cubic FDU-14 with a gyroidal mesostructure of polymer resin or carbon has been synthesized for the first time by using the copolymer Pluronic P123 as a template in a relatively narrow range. Upon calcination at 350 °C, the templates should be removed to obtain mesoporous polymers, and further heating at above a critical temperature of 600 °C transforms the mesoporous polymers to the homologous carbon frameworks. The mesoporous polymer resin and carbon product materials exhibit ordered structures, high surface areas, (670−1490 m2/g), large pore volumes (0.65−0.85 cm3/g), and uniform, large pore sizes (7.0−3.9 nm), as well as very thick pore walls (6−8 nm). The carbon open frameworks with covalently bonded constructions and thick pore walls exhibit high thermal stability (>1400 °C). Our results show that the feed gas used during the calcination has a great influence on the porosity of the products. The presence of a small amount of oxygen facilitates the large pore sizes and high surface areas of mesoporous materials with different mesostructures. An extraction method employing sulfuric acid can also decompose the template from hexagonal mesostructured polymers with little framework shrinkage. Preliminary studies of the mechanical and electrochemical properties of mesoporous carbon molecular sieves are also presented.

Ultrahigh stability (>1400 °C) is found for the highly ordered mesoporous polymers and carbon frameworks synthesized from polymerization of phenol and formaldehyde around triblock copolymer templates. Calcination and carbonization lead to removal of the templates and formation of hexagonal and cubic carbon mesostructures with large uniform pores and surface areas (see schematic diagram).

Highly ordered mesoporous polymer-silica and carbon-silica nanocomposites with interpenetrating networks have been successfully synthesized by the evaporation-induced triconstituent co-assembly method, wherein soluble resol polymer is used as an organic precursor, prehydrolyzed TEOS is used as an inorganic precursor, and triblock copolymer F127 is used as a template. It is proposed for the first time that ordered mesoporous nanocomposites have "reinforced concrete"-structured frameworks. By adjusting the initial mass ratios of TEOS to resol, we determined the obtained nanocomposites possess continuous composition with the ratios ranging from zero to infinity for the two constituents that are "homogeneously" dispersed inside the pore walls. The presence of silicates in nanocomposites dramatically inhibits framework shrinkage during the calcination, resulting in highly ordered large-pore mesoporous carbon-silica nanocomposites. Combustion in air or etching in HF solution can remove carbon or silica from the carbon-silica nanocomposites and yield ordered mesoporous pure silica or carbon frameworks. The process generates plenty of small pores in carbon or/and silica pore walls. Ordered mesoporous carbons can then be obtained with large pore sizes of approximately 6.7 nm, pore volumes of approximately 2.0 cm(3)/g, and high surface areas of approximately 2470 m(2)/g. The pore structures and textures can be controlled by varying the sizes and polymerization degrees of two constituent precursors. Accordingly, by simply tuning the aging time of TEOS, ordered mesoporous carbons with evident bimodal pores at 2.6 and 5.8 nm can be synthesized.

By employing an organic-organic self-assembly in a dilute aqueous solution, novel ordered bicontinuous cubic mesoporous polymers and carbons with Iad symmetry are directly synthesized.

Außergewöhnlich stabil (>1400 °C) sind die hochgeordneten mesoporösen Polymere und Kohlenstoffgerüste, die über die Polymerisation von Phenol und Formaldehyd um Triblockcopolymer‐Template erhalten wurden. Durch Calcinierung und Verkohlung wurden die Template entfernt, und es entstanden hexagonale und kubische Kohlenstoffmesostrukturen mit großen einheitlichen Poren und Oberflächenbereichen (siehe schematische Darstellung).

This paper studies the impact of strategic customer behavior on supply chain performance. We start with a newsvendor seller facing forward-looking customers. The seller initially charges a regular price but may salvage the leftover inventory at a lower salvage price after random demand is realized. Customers anticipate future sales and choose purchase timing to maximize their expected surplus. We characterize the rational expectations equilibrium, where we find that the seller's stocking level is lower than that in the classic model without strategic customers. We show that the seller's profit can be improved by promising either that quantities available will be limited (quantity commitment) or that prices will be kept high (price commitment). In most cases, both forms of commitment are not credible in a centralized supply chain with a single seller. However, decentralized supply chains can use contractual arrangements as indirect commitment devices to attain the desired outcomes with commitment. Decentralization has generally been associated with coordination problems, but we present the contrasting view that disparate interests within a supply chain can actually improve overall supply chain performance. In particular, with strategic customer behavior, we find that (i) a decentralized supply chain with a wholesale price contract may perform strictly better than a centralized supply chain; (ii) contracts widely studied in the supply chain coordination literature (e.g., markdown money, sales rebates, and buyback contracts) can serve as a commitment device as well as an incentive-coordinating device; and (iii) some of the above contracts cannot allocate profits arbitrarily between supply chain members because of strategic customer behavior. This paper studies the impact of strategic customer behavior on supply chain performance. We start with a newsvendor seller facing forward-looking customers. The seller initially charges a regular price but may salvage the leftover inventory at a lower salvage price after random demand is realized. Customers anticipate future sales and choose purchase timing to maximize their expected surplus. We characterize the rational expectations (RE) equilibrium, where we find that the seller's stocking level is lower than that in the classic model without strategic customers. We show that the seller's profit can be improved by promising that: either quantities available will be limited (quantity commitment) or prices will be kept high (price commitment).In most cases, both forms of commitment are not credible in a centralized supply chain with a single seller.However, decentralized supply chains can use contractual arrangements as indirect commitment devices to attain the desired outcomes with commitment. While decentralization has generally been associated with coordination problems, we present the contrasting view that disparate interests within a supply chain can actually improve overall supply chain performance. In particular, with strategic customer behavior, we find that: (...

Upconversion (UC) phosphors emit high-energy photons when they are excited by low-energy photons. This property is attractive for flat-panel displays, [1,2] optical storage, [3] biolabels, [4] solid-state lasers, [5] and light-emitting diodes.[6] High UC luminescence efficiency is typically generated by bulk materials [1] and colloidal nanocrystals [7] of hexagonal-phase lanthanide-doped rare-earth fluorides, but nanoarrays of single crystals are more desirable for solid-state lasers. The UC luminescence efficiency can be enhanced if the nanoarrays are aligned with photonic-crystal microstructures, and the faceted end planes of well-shaped crystals serve as good laser-cavity mirrors.[8]Herein, we report a general solution-based approach for the preparation of uniform nanostructured arrays of the sodium rare-earth (M) fluorides NaMF 4 . The arrays can be prepared with well-controlled morphologies (tubes, disks, or rods), phases (cubic or hexagonal), sizes (80-900 nm), and compositions. This approach avoids the assistance of templates, applied fields, and undercoating on substrates, [9,10] and is industrially feasible, owing to its ease and low cost. Multicolor UC fluorescence is also generated when the nanoarrays are pumped in the near-infrared (NIR) region; for example, green or blue fluorescence is produced for nanoarrays of NaYF 4 codoped with Yb 3+ and Er 3+ , or Yb 3+and Tm 3+

A facile aqueous pathway has been demonstrated for the synthesis of ordered mesoporous carbon materials with hexagonal or cubic structures through the self-assembly of phenol/formaldehyde resols and triblock copolymer templates. Highly ordered mesoporous carbons FDU-16 with body-centered cubic structure (space group Im3̄m) have been synthesized under a basic aqueous condition by using triblock copolymer Pluronic F127 (EO106PO70EO106) as a template. Hydrocarbon (hexadecane or decane) can be used in the Pluronic P123 (EO20PO70EO20) system as a swelling agent to synthesize highly ordered mesoporous carbons FDU-15 with 2-D hexagonal (p6m) structure. The pore size of FDU-15 can be tailored from 4.1 to 6.8 nm by simply varying the hydrocarbon molecules. Mesoporous carbon materials FDU-14 with bicontinuous cubic (Ia3̄d) structure can be formed at a P123/phenol molar ratio higher than 0.04. A phase transformation from Ia3̄d to p6m occurs as the P123/phenol ratio decreases. It is proposed that the cooperative assembly of resols and triblock copolymers driven by one-layer hydrogen bonds between the PEO segments and resols in aqueous solutions may favor the formation of mesostructures. Moreover, the morphology of the obtained mesoporous carbon materials can be controlled on the millimeter (1−5 mm) or micrometer (5−200 μm) scale. The simple aqueous route can give materials with a diversity of structures and morphologies, and this may offer the obtained materials very promising application prospects.